Some gamblers may not take decentralized or centralized betting sites into account. Fiat betting sites also ask customers for KYC.
But I don't know, I don't really care to compare crypto betting and fiat betting. They develop their market based on their own sectors. Fiat betting sites still have their own fans. They reach customers who do not have crypto and are not knowledgeable about it.
Those of us who prefer crypto betting sites also use them and are happier because we have crypto. Otherwise, we might as well bet with Fiat.